Phosphorylated heterocyclic compounds as herbicides

ABSTRACT

METHOD OF CONTROLLING PLANT LIFE WITH PHOSPHORYLATED HEREOCYCLIC COMPOUNDS OF THE FORMULA   R-O-(R1-O-)P(=X)-S-ALKYLENE-(R3-)C&lt;(-N(-R2)-Q-X-)   WHEREIN R AND R&#39;&#39; ARE LOWER ALKYL; X IS OXYGEN OR SULFUR; R2 IS H, LOWER ALKYL;R3 IS H, ALKYL OF 1 TO 3 CARBON ATOMS; AND Q IS ETHYLENE, PROCYLENE OR PHENYLENE.

United States Patent 3,666,435 PHOSPHORYLATED HETEROCYCLIC COMPOUNDS AS HERBICIDES Glenn R. Price and Edward N. Walsh, Chicago Heights, 111., assignors to Staulfer Chemical Company, New York, N.Y.

No Drawing. Original application Dec. 28, 1964, Ser. No. 421,609, now Patent No. 3,580,922, dated May 25, 1971. Divided and this application Nov. 28, 1969, Ser.

Int. Cl. A01n 9/36 US. Cl. 71-87 6 Claims ABSTRACT OF THE DISCLOSURE Method of controlling plant life with phosphorylated heterocyclic compounds of the formula wherein Rand R are lower alkyl; X is oxygen or sulfur; R is H, lower a1ky1;R is H, alkyl of l to 3 carbon atoms; and Q is ethylene, propylene or phenylene.

wherein alkylene represents a polymethylene bridge having from 1 to 3 carbon atoms; R and R are lower alkyl; the radicals represented by X are independently selected from the group consisting of sulfur and oxygen; R is selected from the group consisting of lower alkyl and hydrogen, R is selected from the group consisting of alkyl of from 1 to 3 carbons and hydrogen; and Q is selected from the group consisting of ethylene, propylene,

and phenylene. R, R and R include both straight and branched chain alkyl having from 1 to 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, amyl, octyl, and the like. R is preferably lower alkyl, straight or branched, having from 1 to 3 carbon atoms such as methyl, ethyl, propyl, and isopropyl.

The general process for preparing the compounds of the invention may be illustrated by the following reaction wherein R, R, R R X, Q and alkylene are the same as defined hereinbefore, although the process is not dependent on any particular media, the reaction is preferably carried out in the presence of a relatively inert, normally liquid organic solvent and in this connection it is recommended to use liquid hydrocarbons which form an azeotrope with water (hereinafter referred to as an azeotrope former) such as toluene, benzene, xylene, and the like, so that the water produced in the reaction may be removed through azeotropic distillation. The azeotrope former may also be added after the reaction is completed or well along towards completion so that little is lost through evaporation, or the water formed may be removed by distillation without the use of any azeotrope former. When added initially to the reaction mixture, the azeotrope former acts as a solvent.

The temperature of the reaction is not critical, but should not be so high as to cause decomposition of the product or so low as to require an excessively long reaction time. A workable temperature range extends from about 30 C. to about C. with a preferred range in the vicnity of 25 C. to 60 C. I

In the preferred process, stoichiometric quantities of the amino compound and the phosphorylated aldehyde or ketone are mixed with an azeotrope former, reacted and distilled under partial vacuum. The azeotrope is condensed and the heavier water layer is separated. The azeotrope former is then removed upon concentration of the product.

The following non-limiting examples illustrate the preparation of the novel compounds of the invention.

EXAMPLE 1 s Nn-oHi (n-CaH 0)l SCH CH To a three necked reactor flask fitted with a thermometer, stirring rod and Barrett trap fitted with a condenser, were added ml. benzene, 30.7 grams (0.12 mole) of -0,0-(di ni-propyl)-S-(formyl methylene) dithiophosphate and 7.3 grams (0.12 mole) of amino ethanol. The mixture was then refluxed under vacuum while maintaining the temperature of the mixture at 50.C; until a theoretical amount (0.12 mole) of water was removed. The product was then concentrated to 58 C. at 1.5 mm. Hg to give 29.9 grams (83.5% yield) of 2- [0,0-di n-propyl phosphorothiomethylene] oxazolidine having an analysis of 9.6% P and 20.3%.S as compared to theoretical percentages of 10.3% P and 21.2% S.

EXAMPLE 2 I 8 NH cimoni -somo-ona To a three necked reaction flask containing a thermometer, stirring rod, and Barrett trap fitted with a condenser, were added 150 ml. benzene, 31.5 grams (0.13 mole) of 0,0-(diethyl)-S-(acetylmethylene) dithiophosphate an 16.3 grams (0.13 mole) o-amino benzenethiol. The mixture was then refluxed under partial vacuum while maintaining the temperature of the mixture at 60 C. until a theoretical amount (0.13 mole) of water was removed. The product was then concentrated to 60 C. at 1.5 mm. Hg to give 42.5 grams (94.5% yield) of 2-[0,0- diethyl phosphorodithiomethylene] 2-(methyl)-1,3 benzothiazoline, having an analysis of 8.3% P and 27.2% S as compared to theoretical percentages of 8.8% P and 27.4% S.

The following specific compounds may be prepared in accordance with the procedure shown in Examples )1 and 2, the yields indicated. Sample analyses are included in H EXAMPLE 4 cm S ITCH1 n-mmojiiLs-cmo n OC H2 2 [0,0 di 11 propyl phosphorodithiomethylene]-N- methyl-1,3-oxazolidine; yield=95.5% of theory; analysis:

9.8% P and 20.8% S as compared to 9.9% P and 20.5% S, theoretical.

2-[0,0 dimethyl phosphorodithiomethylene] -2- (math yl) 1,3-oxazolidine; yield=92% of theory; analysis: 13% P and 24.1% S as compared to 12.1% P and 24.8% S, theoretical.

EXAMPLE 6 2-[0,0-dimethyl phosphorodithiomethylene]-1,3-benzthriazolidine; yield 94.5% of theory; analysis: 9.7% P and. 29.9% 8 compared to 9.7% P and 31.1% S, theoretical.

2 [0,0 di n-propyl phosphorodithiomethylene] -2 (methyl) 1,3-oxazolidine; yield 98% of theory; analysis: 9.8% P and 20.2% S compared to 9.9% P and 20.4% S,

theoretical.

EXAMPLE 8 S O-CH2 (u-CzHI) al -S C HzC H N-C H2 Z-[CLO-di n-propyl phosphorodithiomethyleneJ-N-Octyl 1,3-oxazolidine; yield 98% of theory; analysis: 8.6%? and 18.5% S compared to 7.9% P and 16.1% S, theo- 'retical.

EXAMPLE 9 (EH; s NCH2 (C2H50)zi SCHzC-CH3 I 2- [0,0-diethyl phosphorodithiomethylene] -2-(methyl) N-methyllfi-oxazolidine; yield=98.2% of theory; anal- EXAMPLE 10 NC H3 u (C2H5O)2P=SCH2COH3 I {Sr-9m Q 2- [0,0-diethyl phosphorodithiomethylene] -2-'(rnethyl) 1,3-thiazolidine; yield=9l.5% of theory; analysis: A 9.9 P and 30.8% S compared to 10.3% P and 318% S, theoretical.

EXAMPLE 11 I S /S('JH2 (ozmopi -somo-fi 013,

N-CH1 H 2-[0,0 diethyl phosphorodithiornethylene]tetrahydro thiazine.

EXAMPLE 12 H S-CH: wmmm-somozr 1 CH1 N-CH: H

2- [0,0 dimethyl phosphorodithiomethylene]tetrahxr droopazine. l

The compounds of the present invention were tested for herbicidal activity on a variety of economically important plant ,speices. Unusually high herbicidal activity was observed against pinto bean when typical compounds 9 of the invention were applied as a post-emergent spray.

The following table illustrates the general herbicidal activ ity of the phosphorylated oxazolidinesand thiazolidines when used as pre-emergence and post-emergence sprays on a group of common weed pests. The data on extent of injury obtained from plant physiological tests are reported hereinafter as for slight injury (25% .to 35% control), for moderate injury (55% to 65% control), and for severe injury to control). To more specifically define the type of injury ob served, the superscripts LB (leaf burn), MF (leaf malformation), 1C (inhibited germination), ST (stunting) and TK (tip kill) are shown when applicable. The following reference characters representthe indicated plant species tested: C=crabgrass, P=pigweed, L=pinto bean, and W=watergrass.

TABLE.HERBICIDAL ACTIVITY OF PHOSPHORYLATED OXAZOLES AND THIAZOLES ON SELECTED WEED SPECIES Compound, (Example Mode of No.) application 0 P L W 1 Pro-emergence" Post-emergence 2 Pro-emergence 3 Post-emergence- 4 do +++TK +1.13 5 Pre-emergenee Post emergence- 6 o 7 o -l-++:

8- do 9 "do 10 do Pre-emergence herbicidal tests were conducted following planting, but prior to emergenceof the plants, usually the day followingplanting. The active compounds were applied to a. concentration of 20 lbs. of active material diluted in water to a volume of 143 gallons for each planted acre treated. The aqueous herbicidal solutiqng r dispersion was simply sprayed on the pre-planted soil from a hand sprayenAfter fourteen days, plants were inspected and compared with an untreated control group planted on the same day.

Post-emergence herbicidal tests were initiated approximately two weeks following the emergence of new plants. The method of application involved spraying on the plant foliage a 0.5 aqueous solution or dispersion of active compound to the point of run-off. A concentration of active material when spraying the solution was approximately 20 lbs. per acre diluted to a spray volume of 475 gallons per acre. Evaluation of herbicidal activity was made after fourteen days.

Although the above tests were accomplished with aqueous dispersions or solutions, the toxic compounds may also be used in the form of wettable powders, vapors and dusts, as may be best suited to the conditions of use. For more specialized application, the toxicant material may even be used in its pure, undiluted form.

The foregoing description is given for clearness of understanding only and no unnecessary limitations should be understood therefrom as modifications will be obvious to those skilled in the art.

We claim: 7

1. A method of controlling plant life which comprises applying to the locus thereof a herbicidal amount of at least one compound of the formula wherein alkylene is a polymethylene bridge having from 1 to 3 carbon atoms; R and R are lower alkyl; the groups represented by X are independently selected from the group consisting of sulfur and oxygen; R is selected from the group consisting of lower alkyl and hydrogen; R is selected from the group consisting of alkyl of from 1 to 3 carbons and hydrogen; and Q is selected from the group consisting of ethylene, propylene, and phenylene.

2. The method of controlling plant life which comprises applying to the locus thereof a herbicidal amount of 2-[0,0-dimethyl phosphorodithiomethylene] l,3-benzo thiazolidine.

3. The method of controlling plant life which comprises applying to the locus thereof a herbicidal amount of 2- [0,0-di n-propyl phosphorodithiomethylene] -2(methyl) 1,3-oxazolidine.

4. The method of controlling plant life which comprises applying to the locus thereof a herbicidal amount of 2- [-O, O-di n-propyl phosphorodithiomethylene] N-octyl-1,3- oxazolidine.

5. The method of controlling plant life which comprises applying to the locus thereof a herbicidal amount of 2-[0,0-diethyl phosphorodithiomethylene]-2(methyl) N-methyl 1,3-oxazolidine.

6. The method of controlling plant life which comprises applying to the locus thereof a herbicidal amount of 2-[0,0-diethyl phosphorodithiomethylene]-2(methyl) 1,3-thiazolidine.

References Cited UNITED STATES PATENTS 2,490,392 12/ 1949 Whetstone 260-307 3,166,565 l/ 1965 Rigterink 7187 3,159,645 12/ 1964 Rigterink 71-87 3,099,106 7/1963 Edgar 7187 LEWIS GO'ITS, Primary Examiner G. HOLLRAH, Assistant Examiner US. Cl. X.R. 71-76 

